The present invention relates to a railroad toggle switch.
The railroad toggle switch is conceived for a plurality of switching positions and comprises a housing, an operating lever supported on the housing and having a pivot axis, a switching cylinder supported on the housing and having a rotational axis, a plurality of microswitches and an engaging mechanism for engagement of the operating lever in the switching positions. The switching cylinder normally includes a plurality of cam disks for operating the microswitches.
Such a railroad toggle switch has been known from the prior art since a long time and is used in the control panels of trains, subways, etc. In these railroad toggle switches known from the prior art, the operating lever is made integral with the switching cylinder or is firmly connected thereto. The pivot axis of the operating lever is thus coincident with the rotational axis of the switching cylinder. The outer dimensions of the railroad toggle switch are mostly standardized by the train manufacturers, whereby exchangeability in the control panels is to be ensured.
As a result of the standardization of the outer dimensions of the railroad toggle switches, both the number of the microswitches that can be operated by the switching cylinder and the possible switching positions are limited. In the construction of a railroad toggle switch known from the prior art, the microswitches are arranged at the side of the switching cylinder that is opposite the operating lever, i.e. underneath the switching cylinder. A schematic illustration of a railroad toggle switch known from the prior art is shown in FIG. 1. The engaging mechanism is not illustrated. In the direction of the rotational axis of the switching cylinder, several microswitches are arranged one after the other. The maximally possible number of microswitches is given by the standardized outer dimensions of the railroad toggle switch and by the minimum dimensions of the microswitches which are needed because of the desired switching capacity. An arrangement of additional microswitches e.g. at the right or left side of the switching cylinder is not possible due to the closeness of the rotational axis of the switching cylinder to the housing top side and due to the associated limited space conditions. If the rotational axis of the switching cylinder, which constitutes the pivot axis of the operating lever at the same time, was displaced further downwards, the operating lever could no longer be pivoted to a sufficient degree. As a rule, three switching positions are possible in the railroad toggle switches known from the prior art. If more than three switching positions are desired, which is imperative for an independent operation of a plurality of microswitches, the pivotal range of the operating lever must also be enlarged. This is only possible if the pivot axis of the operating lever is moved further to the housing top side. However, since the pivot axis of the operating lever coincides with the rotational axis of the switching cylinder, this prevents a lateral arrangement of the microswitches. A further drawback of the railroad toggle switches known from the prior art is an inadequate splash-water protection due to the relatively large housing opening that is needed for pivoting the operating lever. The opening is the larger the more the pivot axis of the operating lever is positioned underneath the housing top side. At any rate a sealing of the housing opening turns out to be difficult and can only be accomplished in an inadequate manner. The railroad toggle switches are preferably installed on horizontal control panels. Since in the railroad toggle switches known from the prior art the microswitches must imperatively be arranged underneath the switching cylinder, the poor splash-water protection is further deteriorated as water that has penetrated through the inlet opening can drip in unhindered fashion via the switching cylinder onto the microswitches. A further drawback of the railroad toggle switches known from the prior art is that the pivot angle of the operating lever is bound to be coupled with the necessary rotation of the switching cylinder and turns out to be relatively large as a rule.
Moreover, DE 741078 reveals a cord switch for operating a heating pad. The cord switch comprises a housing, a switching drum, and an operating lever. Terminals arranged on the housing are connected, depending on the switching position, directly by the switching drum or by a conductor extending through the switching drum. To ensure the necessary switching capacity in the case of several switching positions, a transmission device is provided between the operating lever and the switching drum, by which device the rotational angles of the operating lever become smaller than the rotational angles of the switching drum. The switch is not designed for operating microswitches. The housing opening required for operating the operating lever is very large and does not provide adequate protection against splash water.
Since in modern trains more and more devices and functions are served from the control panel, there is a demand for toggle switches by which additional switching positions and the operation of additional microswitches are realized with the same outer dimensions of the railroad toggle switches. Moreover, the demand for additionally operable microswitches is already justified by the fact that in modern transportation systems not only the corresponding device or the desired function has now to be activated by operating a toggle switch, but an information signal must also be sent to the on-board computer by simultaneously operating an additional microswitch.